The heart represents a critical organ for pumping blood through the human or animal body. This blood delivers food and oxygen through the arteries to all of the body's cells, while carrying away waste. The heart also needs a constant oxygen supply for proper functioning.
Coronary artery disease is caused by atherosclerosis when deposits of fat, calcium, and dead cells collect along the inner layers of the artery walls. The resulting plaques narrow the arteries to interfere with the smooth flow of blood. A blood clot (thrombus) can block the artery to stop the passage of blood entirely. If this occurs within a coronary artery, a heart attack may result. A blood clot formed in an artery in the brain may cause a stroke.
Electrocardiographs can be used by physicians to display the electrical activity of the heart. A poor electrocardiograph suggesting the presence of coronary heart disease may prompt the physician to administer a cardiac catherization in which a long, flexible tube called a “catheter” is inserted through an artery in the patient. An injected dye will clearly show the condition of the arteries as the dye travels in the blood through them, as captured by an angiogram X-ray.
While coronary heart disease patients are typically treated by drugs and dietary and exercise regimens, this may be insufficient for some patients. For such patents, a coronary angioplasty may be administered where a catheter with a small deflated balloon attached to its end is inserted into the narrowed area of the artery. By carefully inflating the balloon to push the plaque against the arterial wall, the artery can be enlarged and opened. Proper blood flow can be restored, in more serious cases, tiny metal tubes called stents may be placed in the damaged area of the artery to prop it open.
Catheters may be used in conjunction with other medical devices besides balloon catheters for angioplasties. For example, catheters may apply suction to the bladder or kidneys to drain urine, or administer intravenous fluids like medicines, epidurals, and nutritional supplements. Catheters may also be used by physicians to guide endoscopes with a camera for examining the interior of organs, or lasers for treating veins and organs.
Because catheters must be extremely small in cross section to pass through blood vessels, they are necessarily fragile. A range of polymers like silicone rubber, latex, and thermoplastic elastomers are commonly used to make catheters because these materials are inert and unreactive to body fluids and medical fluids into which they will come into contact during medical procedures. But, such materials are also weak mechanically, and may fracture during handling, transport, or storage.
Thus, catheters and guidewires typically must be contained in protective tubes during storage, transport, and usage. These tubes represent long, hollow bodies made from polymers like high-density polyethylene (“HDPE”) or low-density polyethylene (“LDPE”) which provide impact protection along with required flexibility. The interior diameter of these protective tubes typically are very small for accommodating catheters and guidewires while preventing them from moving too much within the tubes. But, because catheters and guidewires may need to be one foot or longer for medical procedures, these protective tubes must be at least that long.
A need exists therefore within the medical industry for these protective tubes containing medical devices to be coiled, so that they can be managed more easily during medical procedures, and stored and transported in confined spaces. Once coiled, the catheter, guidewire, or other medical device can be threaded through the protective tube.
External mechanical clips are commonly used within the industry to secure catheter or guidewire protective tubing in coiled alignment. U.S. Pat. No. 6,375,006 issued to Samuels, for example, discloses a flat clamp piece containing multiple vertically-aligned holes. Flexible tubing for catheter guidewires must be threaded through corresponding holes in the clips to form a stacked coil with several of these clamps positioned along the circumference of the coiled tubing. While this type of clamp fits around the entire tube, it does not allow the tube to be removed from the clamps very easily. Moreover, these clips allow the individual coils of the tube to rotate with respect to each other out of a flat planar coiled alignment.
A different type of clamp is shown in U.S. Pat. No. 7,104,399 issued to Duffy et al. and U.S. Published Application 2008/0006554 filed by Duffy et al., featuring open-faced clamp with multiple side-by-side channels. The tubing can be press fitted into the channels of a clip with a plurality of these clamps positioned along the circumference of the coiled tubing to form a coil in which multiple windings of the tube are positioned side-by-side. While this type of clamp allows coils of different diameter to be formed, and enables a user to release the tubing from the clamps and then reform a coil of different diameter, the clamps can accidentally become disengaged from the tubing during transport, storage, or handling.
U.S. Published Application 2011/027186 filed by Enns et al. discloses another embodiment of packaged elongated medical devices in which catheter tubing is coiled with multiple windings at the factory and secured in place in a mold. Plastic is then injected into the mold to form permanent clips at predetermined points around the coil circumference. While more secure than the open-faced mechanical clamp because such clips bond to the tubing outer wall, the catheter tubing cannot be separated from these integrally molded clips to adjust the tubing in the field.
U.S. Pat. No. 7,461,741 issued to State et al. shows yet another arrangement for tubing for a catheter or guide wire featuring a closed channel with a “C-shaped” open channel extending from its outer surface. While the catheter or guidewire can be passed through the closed channel, the tube may be snap-fitted into the C-shaped open-channel to form a side-by-side aligned coil.
U.S. Pat. No. 5,344,011 issued to DiBernardo et al. illustrates a package assembly comprising multiple housing units. Each housing contains several channels for receiving a coiled catheter tube winding to align the tube in a secured coil. A T-shaped channel at the bottom of the housing accommodates the T-shaped prong of a separate movable housing unit with an interior channel for accommodating the end of the tube. In this manner, the physicians can slide the tube end along the exterior of the wound coil during a surgical procedure to advance the catheter.
While all of these types of mechanical clamps will secure a catheter tube into a wound coil, they are cumbersome to install around the tubing, and in some cases become easily dislodged in the field. This may result in unwinding of the tube and possible damage to the catheter inside it in the operating room or field. Moreover, the mechanical clips allow the tubing often to twist with respect to the fixed mechanical clamps to allow the windings to rise up with respect to each other from the original planar coiled alignment. This may compound the damage to the medical devices contained inside the tubing, and interfere with the sterile packaging containing the coiled tubing.
It is known within the electrical cord or electrical wire industry to include beads and grooves along the exterior of the insulative casing. The casing with the electrical conductors contained inside can be wound into a coil or stack-looped arraignment with the beads snapped into the cooperating grooves to secure the cord or wire in alignment. Separate mechanical clamps are unnecessary. See, e.g., U.S. Pat. Nos. 2,888,511 issued to Guritz; 6,751,382 issued to McGarvey, and 7,574,778 issued to Marathe. However, solid wire conductors with an equally solid insulative coating around its exterior surface can be more readily coiled and snapped into alignment without worrying about possible damage to the conductor. A hollow catheter tube, on the other hand, can easily be kinked during the coiling process with resulting damage to the catheter contained inside the tube.
U.S. Pat. No. 4,607,746 issued to Stinnette discloses a flexible elongated tube for holding a medical guidewire. The tubing features cooperating projections and C-shaped channels extending from opposite points on the exterior of the tube. The tubing may be wound into a coil with the projections pressed into the mating channels. But, because the tubing of Stinnette is perfectly circular in cross section, the resulting tube coils may twist and easily rotate with respect to the fixed connection points. This allows the windings in the tubing to rise up from their original planar coiled alignment during transport, storage, or handling, and result in the coil becoming unsecured. This is a particular problem for medical devices like catheters or guidewires where they have been sterilized, coiled, and placed in sanitary packaging at the factory. If the coil becomes unsecured inside the package, it cannot be resecured in coiled alignment without opening the sanitary package. The catheter or guidewire can also become damaged inside the unraveling coils. This is why, in part, the medical device industry relies upon separate external clamps for securing protective tubing into coiled alignment in spite of the cumbersome assembly and expense of the clamps.
Therefore, providing a protective tubing assembly for containing medical devices or other long, thin fragile products that can be wound into a coil, and retained via cooperating male and female connectors integrally formed along the exterior of the tubing in a substantially flat planar alignment would be advantageous. Such a coiled tubing should inhibit individual coils from rotating with respect to each other, or rising from the substantially flat planar alignment that can cause the tubing to become unwound inside its packaging or during handling, and damage the medical device or long, thin fragile product contained therein.